Dairy Factory Wastewaters, Their Use on Land and Possible Environmental Impacts - A Mini Review

Abstract

Dairy factory wastewaters are increasingly being considered a valuable resource. However, these waters may also contain contaminants, natural or artificial, that may adversely affect the land to which they are applied. This review investigates dairy wastewaters, factors affecting their composition, some probable effects on land and compounds that may be used to trace the migration of pollutants.Dairy factory wastewaters differ depending on the types of products made by the factory and the treatment afforded wastewaters. In addition to milk and milk by-products, dairy factory wastewaters contain cleaning chemicals that contribute to the salt load, and synthetic compounds.From the limited studies where the effects on dairy processing wastewaters on land have been measured, the consensus of the literature results acknowledges the utility to agriculture can be highly variable and depends on the land to which it was applied and wastewater characteristics including concentrations of phosphorus, nitrogen, carbon and sodium. Excessive applications of nutrients such as nitrogen and phosphorus have resulted in runoff to nearby watercourses.Even fewer studies have investigated the use of organic marker compounds in the dairy industry. Lipids, terpenes and sterols found in the plants consumed by livestock would be useful for identifying pollutants from the dairy industry. However, a library of biological marker compounds and their likely sources is needed before such a technology could be applied more widely.

A review on fermentative hydrogen production from dairy industry wastewater

“…Dairy processing is a high volume water‐consuming industry with water use throughout all process steps including cleaning, sanitization, heating, cooling and floor washing; while wastewater volumes generally range between 2‐ and 3‐fold the volume of processed milk . Dairy plants generate wastewater flows with characteristics that are heavily dependent on the raw materials used, the processing technology and the recovery rate of effluent wastewater . Dairy wastewater is characterized by strong color, offensive odor, high organic content in terms of COD and BOD 5 , high solids (3300–57045 mg L −1 ) and high fat, oil and grease (FOG) content (14.000–24500 mg L −1 ), with smaller amounts of nitrogen (30–46 mg L −1 ) and phosphorus (30–650 mg L −1 ) .…”

Valorization of whey using a biorefinery

“…105 This practice can be seen as sustainable because whey has been reported to provide an adequate substitute for potassic superphosphate, while some soil properties are improved. [106][107][108][109][110] However, adverse changes in soil properties, as well as depressed plant growth, can result at high application rates. It has been estimated that the irrigation of 1 mm 3 of whey results in about 400-600 kg of total salt added per hectare, leading to high salinity levels and minor crop yields.…”

“…Denitrification (the microbial reduction of nitrates to N 2 O and N 2 ) occurs in anoxic zones and when a suitable carbon source is available, and leads to losses (about 5-20%) of the whey nitrogen applied. 107 As N 2 O is an important greenhouse gas, it accounts for additional deleterious environmental effects of land whey application.…”

Lifecycle Greenhouse Gas Analysis of an Anaerobic Codigestion Facility Processing Dairy Manure and Industrial Food Waste

“…25,27,28 Fertilizer displacement was calculated based upon 20% mineralization of organic N 25 and applying the emission factors for fertilizer production and fertilizer emissions discussed above.…”